Wintering waterbirds – just how many are there?
BirdWatch Ireland welcomes the publication of population estimates and trends of Ireland’s wintering waterbirds just published in the March issue of Bird Study, the journal of the British Trust for Ornithology.
Our mild climate and abundance of wetlands makes Ireland highly attractive to well over a million waterbirds each winter. Most of these are migrants from arctic breeding areas – they begin to arrive in the autumn, and can be seen along Ireland’s coastline, especially in the estuaries, on inland wetlands, and some species are even found grazing in fields. Ireland is especially important for Whooper Swan, Greater White-fronted Goose (Greenland race), Brent Goose and Black-tailed Godwit.
These estimates and trends, of 27 wildfowl and 15 wader species, represent the first published since the 1980s. They are mostly based on data collated as part of the Irish Wetland Bird Survey in the Republic and the UK Wetland Bird Survey in Northern Ireland. Some 750 wetland sites throughout the island have been covered during this period by over 500 experienced volunteer observers and staff of partner organisations. This includes most of the estuaries and inland wetland complexes which are well-known waterbird haunts, especially Loughs Neagh and Beg, Dundalk Bay and the Shannon and Fergus Estuary. Visit any of these sites during the winter, and you will be astounded by the sheer volume and variety of waterbirds present – Lough Neagh by itself supports almost 100,000 waterbirds!
This study has shown that the numbers of wintering waterbirds declined by almost 10% between 1994/95 and 2003/04. There were declines in 18 species, the greatest in three diving duck species, Pochard, Tufted Duck and Goldeneye, and three wader species Grey Plover, Lapwing and Knot. However, the news is not all bad – most species migrating from Iceland, Greenland and Canada appear to be faring well. Substantial increases were shown in 10 species – the most notable of these were Barnacle Goose, Brent Goose, Grey Heron, Cormorant, Oystercatcher, Sanderling and Black-tailed Godwit.
For many species, the trends measured are continuations of longer-term changes since the 1970s. The causes of these trends are not fully clear. However, we can speculate that climate change is causing a shift in the distribution of some of our wintering species, especially those migrating from northern Europe and the east (Russia and Siberia), as conditions closer to their breeding areas become more favourable. So while numbers in Ireland might be lower than they were 10 years ago, other countries are supporting more of these birds. Unfortunately this is not the case for all species. For example, it is well known that Knot is declining throughout its range. Many of the declines we have observed are likely to be a consequence of increased economic development which has led to direct habitat loss to industrial and residential development.
The estimates produced were used to produce all-Ireland 1% thresholds – these are essential for measuring the importance of wetland sites in Ireland.
Click here to download Bird Study paper (for personal or professional use only)
The Irish Wetland Bird Survey in the Republic is a joint project of the National Parks and Wildlife Service of the Department of Environment, Heritage and Local Government, BirdWatch Ireland, and formerly the Wildfowl & Wetland Trust. The UK Wetland Bird Survey is a joint project of the British Trust for Ornithology, the Wildfowl & Wetlands Trust, the Royal Society for the Protection of Birds and the Joint Nature Conservation Committee.
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